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About Science Prof OnlineScience Prof Online PowerPoint Resources Science Prof Online (SPO) is a free science education website that provides fully-developed Virtual Science Classrooms, science-related PowerPoints, articles and images. The site is designed to be a helpful resource for students, educators, and anyone interested in learning about science. The SPO Virtual Classrooms offer many educational resources, including practice test questions, review questions, lecture PowerPoints, video tutorials, sample assignments and course syllabi. New materials are continually being developed, so check back frequently, or follow us on Facebook (Science Prof Online) or Twitter (ScienceProfSPO) for updates. Many SPO PowerPoints are available in a variety of formats, such as fully editable PowerPoint files, as well as uneditable versions in smaller file sizes, such as PowerPoint Shows and Portable Document Format (.pdf), for ease of printing. Images used on this resource, and on the SPO website are, wherever possible, credited and linked to their source. Any words underlined and appearing in blue are links that can be clicked on for more information. PowerPoints must be viewed in slide show mode to use the hyperlinks directly. Several helpful links to fun and interactive learning tools are included throughout the PPT and on the Smart Links slide, near the end of each presentation. You must be in slide show mode to utilize hyperlinks and animations. This digital resource is licensed under Creative Commons Attribution-ShareAlike 3.0: Alicia Cepaitis, MS Chief Creative Nerd Science Prof Online Online Education Resources, LLC From the Virtual Biology Classroom on ScienceProfOnline.comScienceProfOnline.com Image: Compound microscope objectives, T. Port Tami Port, MS Creator of Science Prof Online Chief Executive Nerd Science Prof Online Online Education Resources, LLC

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Chemical Shorthand Chemical Symbol -Begins with one or two letters based on elements name. -Q: What if there is more than one element that starts with the same letter? -Example: Carbon (C), Calcium (Ca), Chlorine (Cl) Chemical Formula -“Shorthand” for a compound. -Contains chemical symbols of the elements that make up the molecule. -Numerical subscripts represent number of atoms of each element in molecule. Example: H 2 0 = water; has two hydrogen atoms and one oxygen. -More than one molecule of same type…the group of letters is preceded by number. Example 2H 2 0 = two water molecules. From the Virtual Biology Classroom on ScienceProfOnline.comScienceProfOnline.com Image: Periodic Table of ElementsPeriodic Table of Elements

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Elements, Atoms, Molecules & Compounds Element s → Substances that can’t be broken down any further. Atom → The smallest unit of an element. Two or more atoms joined together chemically: Molecule Molecule containing at least two different Elements: Compound Examples of molecules: Carbon dioxide (CO 2 ) and methane (CH 4 ), molecular hydrogen (H 2 ), molecular oxygen (O 2 ) and molecular nitrogen ( N 2 ). Examples of compounds : Only molecules containing two or more elements, such as carbon dioxide (CO 2 ) and methane (CH 4 ). Q: Explain why all compounds are molecules but not all molecules are compounds. Image: Periodic Table of Elements; Water Molecule, WikiPeriodic Table of ElementsWater Molecule From the Virtual Biology Classroom on ScienceProfOnline.comScienceProfOnline.com

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Two ways to look at molecules and their structures: Electron ModelSpace Filling Model From the Virtual Biology Classroom on ScienceProfOnline.comScienceProfOnline.com Image: Periodic Table of Elements; Water Molecule, WikiPeriodic Table of ElementsWater Molecule

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Chemical Bonding and Electron Valences The electrons in an atom are located at different energy levels. Electrons in the highest energy level are called valence electrons. Number of valence electrons governs an atom’s bonding behavior. Q: What is the max number of valence electrons for a full valence shell? Atoms are much more stable, or less reactive, with a full valence shell. By moving electrons, the two atoms become linked. This is known as chemical bonding. This stability can be achieved one of two ways: - Ionic bond - Covalent bond Images: Carbon, Universe Today WebsiteUniverse Today From the Virtual Biology Classroom on ScienceProfOnline.comScienceProfOnline.com Watch Video: Bill Nye The Science Guy on Chemical ReactionsChemical Reactions

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Compounds Have Their Own Properties Compound has physical and chemical characteristics unique from the elements that make it up Compound has physical and chemical characteristics unique from the elements that make it up Example: NaCl From the Virtual Biology Classroom on ScienceProfOnline.comScienceProfOnline.com Image: Sodium Metal, Chlorine gas, Sodium Chloride in shaker, WikiSodium Metal, Chlorine gasSodium Chloride in shaker Sodium Metal: Na Chlorine Gas: ClSodium Chloride: NaCl Click hereClick here to watch this reaction in action!

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Ionic Bonds Involves transfer of electrons between two atoms. Found mainly … inorganic compounds. Ion = an atom or group of atoms which have lost or gained one or more electrons, making them negatively or positively charged. Q : What are positively charged ions (+) called? Q : What are negatively charged ions (-) called? Click hereClick here for Ionic Bonding Animations From the Virtual Biology Classroom on ScienceProfOnline.comScienceProfOnline.com

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Ionic compounds are made of oppositely charged ions Ionic Bonds are atoms held together by attraction between a (+) and a (–) ion Compound is neutral overall, but still charged on the inside. Makes solid crystals. Images: Halit crystal, Crystal structure of NaCl, WikiHalit crystaCrystal structure of NaCl From the Virtual Biology Classroom on ScienceProfOnline.comScienceProfOnline.com

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Everyday Science Reactions Involving Ions Remember… ion = an atom which has lost or gained one or more electrons, so it’s negatively or positively charged. The Principle of ion exchange is a common water softening method. From the Virtual Biology Classroom on ScienceProfOnline.comScienceProfOnline.com

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Polar vs. Non-Polar Covalent Bonds Polar molecules unequally share electrons between atoms, so have a slight positive charge at one end and a slight negative charge at the other. Non-polar molecules have electrons equally shared between their atoms. Image: Polar water molecule, Non-polar methane molecule, WikiPolar water moleculeNon-polar methane molecule From the Virtual Biology Classroom on ScienceProfOnline.comScienceProfOnline.com

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Water is a very common covalent compound. The lines between the O and H’s indicate a covalent bond Click hereClick here to watch a video that compares Ionic and Covalent Bonds! Image: 2-D diagram of H20 molecule, 3-D diagram of Water Molecule, Wiki2-D diagram of H20 molecule3-D diagram of Water Molecule From the Virtual Biology Classroom on ScienceProfOnline.comScienceProfOnline.com

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Oxidation - Reduction Reactions Or Redox reaction = chemical reactions in which electrons are gained, lost ( Q : What kind of bond?) or shared ( Q : What kind of bond?) in a chemical reaction. oxidation : loss of electrons by a molecule, atom or ion. reduction : gain of electrons by a molecule, atom or ion. From the Virtual Biology Classroom on ScienceProfOnline.comScienceProfOnline.com

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Chemical Bonds hold molecules together, but can be broken during a chemical reaction Reactants are the starting materials Products are the end materials Image: Combustion Reaction of Methane, WikiCombustion Reaction of Methane From the Virtual Biology Classroom on ScienceProfOnline.comScienceProfOnline.com

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Combination, Decomposition & Replacement Reactions Combination Reaction (a.k.a Synthesis or Anabolic Reaction) When two or more substances combine to form a single compound. Requires energy in order to take place The general form of a direct combination reaction is: A + B → AB where A and B are elements or compounds, and AB is a compound consisting of A and B. Examples of combination reactions include: 2Na + Cl 2 → 2 NaCl (formation of table salt) 4 Fe + 3 O 2 → 2 Fe 2 O 3 (iron rusting) Decomposition Reaction (a.k.a. Catabolic Reaction) The opposite of a composition reaction. A compound is broken down. The generalized reaction formula for chemical decomposition is: AB → A + B Replacement Reactions (Transfer or Exchange Reaction) Atoms are moved from one molecule to another. A + BC → AB + C Images: Animation decomposition reaction, Armando-Martin; Rust, Later KeiwosAnimation decomposition reactionRust From the Virtual Biology Classroom on ScienceProfOnline.comScienceProfOnline.com